The most common electrical outlet in the United States is the duplex receptacle. The duplex receptacle has receiving sockets into which the plug prongs of an appliance snuggly fit. Typically, a duplex receptacle has two rectangular or slotted receiving sockets and one arch-shaped receiving socket. Typically, one of the two slotted receiving sockets is larger than the other. This is a polarized receptacle, where the larger slot is the neutral terminal and the smaller slot is the hot terminal. It accommodates appliances that have polarized plugs. The arch-shaped slot is a ground slot, for use with a plug that has a ground prong.
The National Electrical Manufacturers' Association (“NEMA”) has a standard specification, WD6-2002, for the height, width, and depth of a duplex receptacle. In order to retrofit a duplex receptacle into existing construction, it must comply with the dimensional specifications of WD6-2002. In order to be included in new construction, a duplex receptacle must comply with the dimensional specifications of WD6-2002.
The duplex receptacle is generally installed in a duplex outlet housing box that is attached to a wall stud. A duplex receptacle is wired to a building by attaching the hot wire to the hot terminal, and the neutral wire to the neutral terminal. If the duplex receptacle is in an area that might get wet, most building codes require a Ground Fault Circuit Interrupter (“GFCI”). A GFCI has an additional attachment to the home or commercial building: it has a ground wire. Otherwise, the GFCI is dimensionally the same as other duplex receptacles. A duplex receptacle is covered by a face plate, in order to cover the wires. Due to standardization, the cost of the duplex receptacle is very low, with units starting at less than $1.00 at wholesale.
There are many situations in which a person wants to plug an electrical appliance into a duplex receptacle in a room which is dark. The person must either turn on lights in the darkened room, or fumble about trying to find the duplex receptacle. Many times, in order not to disturb those that are sleeping, such as a child or spouse, a person will choose not to turn on the light. In many cases, a room can be so dark that even the outline of the duplex receptacle is indiscernible. Finding the duplex receptacle in a dark room can be difficult, as the person must correctly identify the position of the outlet in the room, overall. Additionally, the person must search at the right height. Electrical outlets that are hidden, or partially hidden, due to furniture placement make the problem even more difficult.
Once the duplex receptacle is located, plugging in an appliance can be challenging. In the dark, it is difficult to correctly align the spades or prongs of the plug with the corresponding openings of the duplex receptacle; especially with respect to polarized plugs (i.e., plugs in which one spade is larger than the other). What is easy in a lighted room—spatially aligning the spades of a plug, with the correct orientation, to a duplex receptacle—can be daunting in the dark. To help with overcoming this issue some consumers expose themselves to electric shock by trying to feel the location of the prongs with their naked fingers, in order to help with proper insertion of the plug.
In addition to convenience, there are some safety issues to consider. A person can shock themselves feeling around for an electrical outlet. A person can easily shock themselves guiding the prongs into the electrical outlet. Additionally, a person can injure themselves bumping into things in a darkened room, or tripping over cords that are already plugged into the duplex receptacle.
What is needed is a duplex receptacle that is backlit so that the receiving sockets are apparent in a darkened room. Such a solution would not, necessarily, act as a nightlight, as it would not add a significant amount of ambient light to the room. Additionally, such a solution would have a very low overall power draw.